#include <stdio.h>

#define N 10000

typedef struct sp_tree{
	int id;
	struct sp_tree *adj[N];
	int visited;
	int n_adj;
}sp_tree;

sp_tree dfs[N];

int max_node;

void d_dfs(int v, int c, int *counter){
	int i;
	c++;
	for(i = 0; i < dfs[v].n_adj;i++){
		if(dfs[v].adj[i]->visited == 0){
			printf("node %d , adj -> %d, c -> %d, counter -> %d\n",v,dfs[v].adj[i]->id,c,*counter);
			dfs[v].visited = 1;
			if(*counter <= c){
				*counter = c;
				max_node = dfs[v].adj[i]->id;
			}
			d_dfs(dfs[v].adj[i]->id,c,counter);
		}
	}
}

void problem_e(int v){
	int counter = 0;
	d_dfs(v,1,&counter);
	d_dfs(max_node, 1, &counter);
	printf("%d\n",counter);
}

void add_vertices(int v1, int v2){

	dfs[v1].id = v1;
	dfs[v1].adj[dfs[v1].n_adj] = &dfs[v2];
	dfs[v1].visited = 0;
	dfs[v1].n_adj++;

	dfs[v2].id = v2;
	dfs[v2].adj[dfs[v2].n_adj] = &dfs[v1];
	dfs[v2].visited = 0;
	dfs[v2].n_adj++;

}
int main(){
	int n;
	int i;
	int v1,v2;
	scanf("%d",&n);
	for(i = 0; i < n; i++){
		scanf("%d %d",&v1,&v2 );
		add_vertices(v1,v2);
	}
	problem_e(v1);
	return 0;
}